Member postings for GrahamS

I did a quick drawing to understand the cylinder end caps dimension issue.

So for both ends this seems right ?

If so luckily I only have to remake the top end cap as I havnt got as far as drilling the cylinder , phew.

Thanks

May thanks Baz , very helpful. Thanks for the offer of future questions

Many thanks Baz,

3 questions please:

1 The valve chest contains 2 valves, one driven off the piston rod and one ( the shuttle valve ) which appears to be self propelled using pressure from the ports.

On the steam chest drawing ( Item 2) , looking at the side elevation , the piston rod driven valve spindle is 0.165 from the cylinder face. But I cant see a dimension for the 0.156 diameter shuttle passage/hole from the cylinder face ? Is it the same as the other valve i.e. 0.165 centre from the cyl face - i.e. both valves the same centre line distance from the cyl face , or something different ?

2 Also on the cylinder (item 1) end view, for the end cap bolt pattern where it says 'copy the bolt pattern from item 5' , these undimensioned bolt patterns on the cylinder do not look the same as the dimensioned ones item 5, which are a simple 0.5" square ? On the cylinder they are not a square , one side appearing wider. I am very aware of the close proximity of the steam chest holding down bolts in this area.

3 How closely do you follow the depth of the 10BA holding down threads on the plan? They seem extremely shallow, the 0.075 cylinder end cap and valve chest holding down bolts for example.

Thanks in advance

Edited By GrahamS on 18/07/2023 17:18:53

Edited By GrahamS on 18/07/2023 17:19:33

Edited By GrahamS on 18/07/2023 17:20:21

I am making good progress with this project, but have come to a halt with lack of dimensions on the steam chest. It is quite probable I am missing something obvious, so if anyone built one of these recently are they open to a question or two ?

Thanks in advance

Excellent thread. Thanks Ian.

Hi Ian,

Did you follow any build logs for your Farm Boy builds?

I am aware of the Andrew Whale one but would like to see others as insurance.

Graham

Thanks for the tank info Ian. I will do something along those lines.

My lifters are not all equal by the way. I don't have measurements to hand, but something around 10 thou difference ? For me , it would have to be out enough to effect running to warrant a remake - do you think this is the case?

I have spent the last week chasing the 'cool' cylinder issue , pressure testing the valves with the head in situ and off, remaking head gasket and leak checking around the inlet manifold etc. I have confirmed the piston rings are doing their job as there is the same compression as the right. All this activity has improved the situation a bit , but the right cylinder remains lazy compared to the left. By that I mean on startup the right starts first, then the left kicks in after a few seconds and the revs pick up and it runs smoother. As it starts fine now , and runs as long as there is fuel I am tempted to call it quits - other projects beckon!.

I fancy a go at a steam weir pump, one small enough to fit on my Sweet Pea. The injector currently fitted is pretty random in operation , so another way to get water in would be handy. Just sizing up the Blackgates ( ex Southwold) and Kennions ones.

Another option I fancy is the Jerry Howell Farm Boy , which usefully like the Hoglet, has an Andrew Whale vlog !

I have enjoyed the Hoglet build as well, and the forum help from yourself, Jason and Rod has been priceless.

Edited By GrahamS on 01/06/2023 09:58:57

That looks great Ian , well done.

Agreeing with Jason, I think your hall sensor position is to do with the advance angle. I notice you say 10* BTDC - on the data sheet supplied with my Rxcel ignition , and confirmed by Just Engines, it should be 28 to 30* BTDC. I suspect this will position your sensor roughly vertical. Interestingly, they also confirmed with this ignition the advance is not adjustable and cant be disabled. In other words we have to live with it and set to and advance of 30* to get a spark at ( or just after?) TDC. They also confirmed the advance feature kicks in at revs higher than the Hoglet will achieve - so apart from conforming to the the angle they advise - we can ignore it ! They commented this feature is aimed at small high revving aero engines. I have trawled the internet for more details on this and drawn a blank. Given it is a reasonably cheap, easy to fit ignition, for future engines I would be interested to see rev vs advance angle data.

To help set the ignition I made a TDC mark ( for the right hand cylinder TDC when viewed from the cam side  on the flywheel. This mark is made close to the engine frame on the right hand side. I then made a small brass sheet pointer which when fastened to the frame by one of the frame bolts, points at the TDC mark. I wanted to take the engine apart to get a better finish on some of the parts anyway and took the opportunity to mount the crankshaft in the lathe to make a mark 30* BTDC, and a 180* ( BDC ) mark.

Timing the cams so the right hand intake closes by the 180* BDC mark ( thanks Rod ) and the timing the ignition so the right cylinder fires as close to the 28* BTDC mark.

I find a reliable startup procedure is to set the carb needle to one turn open, air bypass two turns open, slightly flood the carb with fuel ( thanks Jason ) and go for it. I find this to be a reliable procedure.

Re fuel , I started with Colmans but found it rapidly created soot on the valves and the valve faces needed cleaning regularly to stop sooting up. I now use unleaded pump petrol , mixed 40 to 1 with 2 stroke oil ( thanks Jason ) and it runs much cleaner. This is the same mix as my 2 stroke strimmer - bonus !

Is your fuel tank from a plan ? I am still using a plastic test tank dangling from a piece of string, and would like to make something I can mount on the base like yours. Also where did you get those fluted beams it is supported on?

Thanks

Graham

Edited By GrahamS on 31/05/2023 10:09:30

Hi Ian ,

Its an Enya 52535 6mm bore , 35 quid from Steve Webb models in Frodsham. It looks like  this https://www.ebay.co.uk/itm/293047194494    though that says it has twin needle valves which mine doesnt.

Not having much IC experience I am still getting used to the settings so I can start reliably and get a nice slow tick over , but progress is being made. Flooding it via the intake using a pipette, and having the needle further out than required for running seems to help with starting ! Then when running screw the needle in slightly to get a smoother tickover. This carb has a air bypass control as well - a screw that controls how much air bypasses the throttle so is always supplied - I have found having this just half a turn out helps. As I play with it more I am sure this will evolve.

Where I am currently investigating is, as mentioned above, the right hand cylinder not getting warm when running so it doesnt look like it is doing much. But when I run it just using that cylinder it runs ok ?

Edited By GrahamS on 24/05/2023 19:45:43

Edited By GrahamS on 24/05/2023 19:51:25

A good day ! It runs , but after a fashion seemingly on one and a half cylinders.

One cylinder seems to run hotter than the other? Sparks and timing checked ok on both. It runs on one cylinder at a time ok ( alternatively one plug out at a time to test the other side is ok ). Still puzzling it out.

Edited By GrahamS on 24/05/2023 16:32:08

I do like that dinky petrol tank Rod. Was it from an existing plan or designed on the hoof ?

Thanks Ian, very useful.

Whats your plan to get it running?

Many thanks, it totally went over my head with IC engines you of course have the option to set this in multiple places.

A real doh moment.

Thanks

Hi Jason,Rod,Ian,

I am close to fitting the timing magnets for the Rxcel ignition to the timing gear.

One is fitted as north pole, one south to trigger the correct spark plug. On the drawing, one it fitted 120 degrees before vertical, the other 39 after. I am probably overthinking this, but does it matter which pole is fitted in each position?

If this system uses a specific pole to trigger a specific plug I am thinking the magnet fitting position will be relevant to coincide with the valve timing.

Many thanks

Graham

Excellent , well done. I would be very pleased with that.

Good luck with the test run Rod, and lots of pics ( and vids? ) please.

You are welcome Ian and good luck with the test runs - keep us updated !

Have you settled on a carb yet ? I know next to nothing about model carbs. Jason has kindly suggested any 4 or 5mm bore carb will do , but so far no luck finding anything.

Dont know if you have seen this Rod, Andrew Whale produced a drawing of his sensor attachment ( dont know if its the same type of sensor) and made it available on Youtube.

Pistons machined using the Rod method, all went well apart from the last stage machining out the relief for the little ends of the con rod. I couldnt get a good enough grip in the vice even with very light cuts ( I may well have not been applying enough grip in the vice - scared of squeezing the pistons out of shape ), so used the three jaw chuck in vertical mode in the mill instead which worked well.

Trial assembly shows it turns nice and smooth, and lots of compression with the O rings fitted.

Can I ask what the design 0.125 hole in the centre of the wrist pin button is for ? Seeing this has given me the thought of using a small countersunk screw through this hole into the wrist pin each side to secure the buttons on. Then I can strip it down easily if required.

Also what is the thinking on lubrication after assembly for the little and big ends of the con rods? Has anyone attempted any form of lubrication in this area for between runs ? I am aware it is a demo engine only designed for short runs, but I am happy to do extra work to be able to lubricate these areas, if it is possible. I am toying with an oil hole through the big end boss of the blade rod and through the bearing to to lubricate the crankshaft, placed so it is accessible through the frames between the rods.

The Rexcel V twin ignitions are back in stock at Just Engines if required.

Edited By GrahamS on 28/02/2023 18:16:48

Edited By GrahamS on 28/02/2023 18:17:19